


The Runaway Avenger

by Meatball42



Category: Doctor Who (2005), Marvel Cinematic Universe, The Avengers (Marvel) - All Media Types
Genre: Adventure & Romance, Canon Divergence - Avengers: Endgame (Movie), Crossover, Developing Relationship, F/M, Happy Ending, Infinity Gems, M/M, Male Companion (Doctor Who), Multiverse, Non-Sexual Intimacy, Polyamory, Tenth Doctor Era
Language: English
Status: Completed
Published: 2019-09-09
Updated: 2019-09-09
Packaged: 2020-07-08 17:42:51
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,195
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19873537
Author URL: https://archiveofourown.org/users/Meatball42/pseuds/Meatball42
Summary: When another human appeared in the Tardis, the Doctor decided that Donna must have started a trend. Luckily, it turned out to be a very, very good one.





	The Runaway Avenger

**Author's Note:**

> For Lady_Katana4544
> 
> I have this headcanon that sometimes, while the Doctor is ‘with’ one Companion, he’ll take a century or so off and hang out with some other people. I got the idea from the Eleventh Doctor episode ‘The Impossible Astronaut,’ where he shows up 200 years older than the last time Amy and Rory saw him. This story, then, is slid into canon entirely during Donna’s time with the Tenth Doctor, nominally canon compliant.

Once upon a time, the Doctor had turned around to a very surprised sound in his Tardis and met a wonderful human, a really very truly annoying woman, whom he came to love very much.

So when he heard a very surprised sound in his Tardis and turned around to see a rather upset-looking human, he thought that perhaps this was the second point in a pattern Donna had begun.

“Hello,” he said. “I’m the Doctor. This is my ship. Er… who are you?”

The man was looking around in significant shock. The Doctor understood, of course. Most people in the universe hadn’t had the exciting experience of being in one place, and then suddenly being in another place. It was something of an acquired taste.

The Doctor rocked on the balls of his feet, looking friendly and hopefully-not-frightening-at-all, until the human managed to close his jaw and put a few words into a meaningful order.

“Tony Stark,” he said first. The Doctor figured that was probably a name, because he’d met both Tonys and Starks before, though not a person who was both at the time time. “How did I get here?”

“I’d expect it has something to do with those.” The Doctor gestured vaguely at the intensely radioactive and mind-bendingly powerful artifacts on the human’s hand. He didn’t point, because one oughtn’t point at sentient, extraordinarily powerful beings, oughtn’t one?

The human stared at the gems on his hand. The Doctor hoped he knew what they were. It would be less likely to send him spiralling in shock, for starters, and also, he might know how to make sure they wouldn’t explode inside the Tardis, and the Doctor was really hoping that they wouldn’t explode in the Tardis.

“Shit,” said the human, succinctly.

~ ~ * ~ ~

Once Tony had taken off the Infinity Stones and introductions had been performed and the artifacts had been placed in appropriate containment, and Tony had drunk some coffee ( _‘Heathen!’_ ) and eaten four cheeseburgers and slept for twelve hours and the Doctor had finally got around to fixing the Tardis radio, which had been fuzzy and prone to skipping for decades, they reconvened and explained where each of them was coming from, which left Tony looked rather flabbergasted and the Doctor feeling much more secure about how yet another unexpected guest had managed to pop into his Tardis without warning.

“We don’t have anything like these here, I’d certainly have heard of it by now,” the Doctor thought aloud, staring at the Stones in their containment pod. They twinkled at him as though acknowledging his existence, and he looked away quickly.

“I need to get back,” Tony said. “I have a daughter, she’s five. I promised her I’d come back.”

The Doctor wasn’t really a tactful sort in this incarnation, but he did have a daughter and knew what a temptation it was to tell them that everything would be alright, so he suppressed the _‘Why did you go and say a silly thing like that?’_ which was his first thought. Instead, he said, “I’ll do my best to get you home, Tony. But travelling between universes, it can be next-to-impossible on the best of days. At worst… it can damage the walls separating universes and lead to all sorts of terrible things on both sides.”

Tony stared into his coffee and didn’t say anything.

~ ~ * ~ ~

They decided to hop around to a few different galactic bazaars to look for the right kind of things to prod the Stones with that would hopefully not make them explode, but also produce some useful data.

The Doctor was pleased to see that his instincts about Donna and Tony being two points in a pattern paid off, as the man showed the beginnings of being an excellent Companion. He was brilliant, for a human, absorbing everything the Doctor explained about the Tardis and time travel and interdimensionality and negative resonances and singularities and the sticky bouncy parts in between two twists of a wormhole right up until they reached the eight kinds of matter and Tony said he had a headache and had to go lay down for a while. That was still much better than any other Companion had ever done. He also stopped to help little alien children with broken racing pods and used his flying suit to stop a damaged ship from crashing into a city.

It had been a while since the Doctor had found someone to bring along on his travels who wasn’t very young for their respective species. Tony was twice Martha’s age and nearly three times Rose’s age (well, thrice Rose’s age when she’d first come along with him). It was a pleasant departure, frankly, to travel with someone who didn’t wander off without communicating where they were going on a strange alien planet, who came up with ingenious plans on their own, who were just as good as the Doctor at taking command of a strange situation upon arrival.

It was truly much less stressful than travelling with the young ones. The Doctor considered that he might pick up another like Tony after he was gone. This version of him seemed to like being a partner rather than a shepherd.

Which wasn’t to say that there wasn’t ever so much to introduce Tony to in the universe. The Doctor gleaned from their conversations that Tony was from a time in his universe where Earth had only barely begun to reach out to the stars. Tony’s only experiences with aliens had brought war and suffering for the most part, which was a shame and all-too-common a story of first contacts. But it just meant that Tony was happy to meet kind aliens, to see thriving societies among the stars, to take apart things from millions of years in the future and millions of light-years away from Earth and find out how they ticked.

They had all sorts of lovely adventures and even more lovely exploration and discovery. For the first time in a few centuries, the Doctor’s ratio of landing on peaceful, interesting planets was actually higher than that of unexpectedly landing on a planet that was about to be destroyed, or in front of a settlement that was about to be wiped out, or someone unexpectedly being a plastic clone, or someone else suddenly becoming unsettlingly prone to die all the time, or discovering that a member of his race had unexpectedly Un-Ceased-To-Exist.

And then one day Tony and the Doctor found themselves in the middle of a sticky situation, saved a planet, and were unexpectedly married by the happy populace in the ensuing celebrations. There was a moment in the middle of everything, when Tony had looked at him with a soft smile and leaned up to kiss his cheek, when the Doctor had been concerned. But it turned out that Tony had not, in fact, been harboring romantic feelings for him, which was quite a relief and yet another tick in the ‘Older Companions’ positives list.

They made it back to the Tardis before Tony addressed him with a very serious look on his face.

“Doc,” Tony started, “traveling with you has been the second-most amazing thing that’s ever happened to me, and I’ve had a pretty extraordinary life. But I need to get back to my universe. I think we should stop taking side trips.”

“What, what side trips, I don’t know what you mean,” the Doctor blustered, climbing the steps to the Tardis console and fiddling with the buttons. “She’s got a mind of her own, you know.”

“I know,” Tony said kindly.

The Doctor turned to see Tony smiling up at the Tardis, one hand patting the steel beam she’d grown not long after Tony’s appearance. The marriage pendant he’d placed around Tony’s neck at the ceremony just hours before was still hanging there, although Tony’d had any number of opportunities to take it off.

The Doctor realized he hadn’t even fought the marriage that much, because for once, he and his Companion where on the same page, and they knew what it didn’t mean, and, just maybe, they each appreciated what it did. 

Twin pangs went through the Doctor’s chest. He’d always know it would have to come to an end, but… he was never good at admitting that sort of thing.

Tony looked at him suddenly and read his expression before the Doctor could turn around. He came up to the console and pulled the Doctor into a hug.

The Doctor let him, even snuggled in. It had been years since he’d had someone comfort _him_ like this, but… well, Tony was a parent who hadn’t seen his child in a while and was probably feeling a bit of comforting-someone-else withdrawal. Really it was he, the Doctor, doing _Tony_ a favor.

“Between the two of us, I bet we can rig up some inter-universal FaceTime,” Tony said quietly. “I’m not planning on leaving you high and dry, Doc.”

The Doctor hugged him tighter and pretended he wasn’t sniffling. It was just that this incarnation was prone to sympathetic tears, that was all, and parting was always such sweet sorrow. And anyway, “What’s this FaceTime?”

Tony laughed.

The marriage pendant the Doctor had tucked under his own shirt dug into his chest, and although Tony must have been able to feel it, he didn’t say a thing.

~ ~ * ~ ~

Once they really got down to it, it was only a matter of a week or two before they managed to get the Tardis to communicate with the Infinity Stones to please, return to their own universe and bring their attached human with them. Asking nicely, it turned out, was the secret to operating the Stones without loss of life or limb, and the Tardis had a very nice chat with them.

When the Doctor communicated this to Tony, he rolled his eyes and said, “That figures.”

“This’ll send me back right after I left, right?” Tony asked, when he’d collected all of his mementoes from their travels and a scarf out of the Tardis wardrobe and a box of chocolates the Doctor just happened to have lying around and also a sandwich, just in case, because you might never know where you’d land. “Because I was sorta counting on that this whole time.”

The Doctor asked the Tardis, who asked the Stones, who told her, who told the Doctor, who told Tony, “They say yes.”

Tony, who’d watched all this and looked uneasy but also long-suffering and as though he expected this sort of thing by now (which was very mature of him, the Doctor thought affectionately), sighed.

“Time to go, I guess.”

“Oh yes, I guess indeed, time to be off,” the Doctor cleared his throat, “of course.”

Tony gave him a look that was frustratingly reminiscent of Donna and her know-it-all-annoyingness, and hugged him. He even kissed the Doctor on the cheek, which made him blush, which he disguised by holding Tony tighter and tucking his face into Tony’s neck, and that was the only reason for that.

“I am going to set up that FaceTime, okay? And I’m going to get my friends Nebula and Carol to compare notes with you about planets in our world. And you’re going back to New New New Río and finding out what it was I ate right before the palace came under attack so I can try to make it back home.”

The Doctor let Tony fuss and ignored the way Tony called someplace else home.

The Stones let out an impatient wobble a few dimensions above Tony’s senses, and the Doctor sighed and Un-Hugged them. 

Tony put on the gauntlet that held the Stones and the Doctor panicked a tad.

“Tony, I have to tell you, because inter-universal travel has a tendency to go awry, and I don’t want you to leave thinking—”

“It’s okay, Doc,” Tony interrupted with a fond grin. “I already know. You don’t have to give yourself a hearts attack.”

“Well… good then.” 

And Tony smiled at him one last time, and snapped his fingers, and was gone.

The Doctor waited, but when an hour or so had passed and none of his screens popped to life with a communication, he thought that that must be that.

“Off on another one, eh old girl?” he said to the Tardis, and flicked a few switches.

She started flying and he left the destination in her capable hands.

~ ~ * ~ ~

The Doctor didn’t have an awful time after Tony left. Every Companion left in the end, some more happily than others. The Doctor flew around for a while, grieving in his own way, until he was ready to pick Donna up and have fun again. It was good to see a friend, to be reminded that the end of one thread did not mean the end of the tapestry.

A number of adventures later, the Doctor was buried chest-deep in the engine of a stranded spaceship, helping the confused owners identify what had gone wrong, when his sonic screwdriver buzzed at him. There was a specific pattern to let him know that the phone was ringing back in the Tardis, so he toggled the call with the Later switch.

He headed back for the Tardis shortly. Donna had found a new friend to gossip with about space fashion and make fun of the local politicians, so he left her to enjoy herself. He was expecting a call from Martha, and it would be good to have some privacy.

The sonic reminded him of the call as he crossed the threshold, and he toggled the Later switch back to Now. Instead of the console phone ringing as expected, familiar red gem appeared in the air before him.

As the Doctor watched, the gem shimmered outward in two dimensions, creating a flat surface facing him. After a moment, the ruby glow shifted into a multi-colored image.

“Hey Doc,” said Tony. He was smiling, bright-eyed, with lines on his face deeper than the Doctor remembered. But they were happy lines.

“Can you say ‘Hi Doctor’?” asked a red-headed woman at his side, waving at him.

“Hi Doctor!” chorused two young beings in their laps.

“Well hello there!” the Doctor said gleefully. “Aren’t you all a sight for sore eyes!”

“This is my wife, Pepper, and our kids, Morgan and Kobik. Everyone, this is my good friend the Doctor.”

“Spaceship!” the pink one exclaimed.

“Time Vortex!” the blue one shouted back.

“Tony’s told us about how you helped him get back home and showed him all sorts of amazing places in space,” Pepper said, stroking the pink one’s hair. “All of us wanted to say thank you for bringing Daddy home.”

“Thank you!” the kids squealed in unison.

“It was my absolute pleasure,” the Doctor told them honestly. “Your dad’s a good man to have around a spaceship.”

“About that,” Tony started. “You remember the Infinity Stones, right Doc?”

“Of course I do.”

“Well Kobik here is one of those Stones, in human form. She got curious after going through space and time with us and talking to the Tardis, and wanted to try out living like one of us for a while.”

The Doctor stared at the girl on Tony’s lap, who watched him back with an innocence that belied her eternal nature. “You’re a very special little one, aren’t you?”

She grinned and fell back like small humans did, trusting her father to catch her and haul her back to upright.

“When I got back home, most of the Stones disappeared. Kobik stayed. It took her a few months to figure out how to contact you without destroying reality, but we figured it out.”

Kobik giggled.

“In a few years, she’ll have enough control for us to make a visit. How does that sound?”

Tony took his wife’s hand while he watched the Doctor, love and excitement in his gaze.

The Doctor shook his head, overjoyed at the idea of Tony and his family running around the Tardis, filling it with laughter and fun and probably some shouting and tears, too, because the humans always did that, but no less wonderful for it all.

“Stupendous!” he shouted. “We’ll have the whole family over, eh? I’ll find us some safe, _completely_ risk-free places to visit, no chance of any danger at all!”

“Good,” Pepper said firmly.

“Well,” Tony prevaricated, “by then, they could be old enough for—”

“No.” Pepper didn’t even taking her eyes off the Doctor.

“Hey, Clint’s kid is in training and she’s only—”

_“No.”_

“I wanna be a space ‘venger!” Morgan whined, tugging at her mother’s hair.

“Can I fly in the Time Vortex?” Kobik asked her father. She started to float up from his lap in excitement until he wrapped his arms around her and gentled her back down.

“We’ll have to ask the Doctor when we get there, it’s his ship,” Tony told her.

“Only if it’s safe,” Pepper insisted.

“Everything on my Tardis is safe!” the Doctor insisted.

Tony snorted and Pepper narrowed her steely eyes at the Doctor.

“Well… tell me how you’ve been,” he changed the subject quickly.

He sat down in the chair next to the console, the portal to another world following him easily. Tony and his kids all started talking at once, and the Doctor settled in happily to catch up with his future Companions.

After he'd been shown Morgan's drawing of the Tardis (nothing like how she looked, but she _could_ look like that quite easily) and Kobik had tried to fly away twice more, Pepper sent the young ones to play outside. She and Tony met each other’s eyes, and then Tony started to unbutton his shirt.

He pulled out a very familiar pendant. The Doctor’s breath caught in his throat.

“Remember this?” Tony asked the Doctor softly.

“You still wear it?”

“Of course. I wear this, too.” Tony held up his other hand, where there was a ring on his fourth finger. “I’m pretty lucky. I’m the only guy I know who got to marry two people.”

Hearts beating double-time in his chest, the Doctor looked at Pepper. “And you… You’re from Earth, well, 21st century Earth, you can’t be used to this.”

“No, I can’t say it’s normal to have a husband who’s also married to an alien,” said Pepper. She raised an eyebrow at Tony. “When he appeared out of thin air and told me what happened, I had no idea what to think. But if I wanted normal, I married the wrong guy. And I made my peace with that a long time ago.”

She slipped an arm around Tony’s waist and leaned her head on his shoulder. Tony pulled her closer and kissed her hair, still holding the marriage pendant in his hand 

“I couldn’t wait to meet you,” Pepper said to the Doctor sincerely. “Tony’s told me all sorts of stories.”

“I’ve heard stories about you, too,” he murmured.

Tony hugged Pepper closer and smiled at the Doctor. “Someday we’ll get to make stories together, huh?”

The Doctor touched one of his bottomless pockets, where his marriage pendant remained, coiled up with its string. “Can’t wait.”


End file.
